Modern conventional ski-boots offer an example of footwear with relatively flat, non-bending soles. Other examples include foot covering made inflexible by plaster of Paris or otherwise braced for special medical or mechanical reasons, but this invention will be described in combination with ski-boots, the most common and widely used flat, rigidsole footwear.
Known in the art are the showings of the following U.S. Pat. Nos.:
1,938,617 to A. Augusta, Dec. 12, 1933, showed a strap-attachable member with heel and a sole that extends forward to the metatarsal area forming a pivotal support for walking without need to flex the shoe;
2,278,626 to J. R. Vasko, Apr. 7, 1942, showed a lace-up rounded bumper of rubber or the like that can be attached under a rigid cast on the foot to make it easier to walk;
2,423,354 to F. B. Van Hosen, July 1, 1947, showed a zipon boot with a "U"-shaped metal "walking iron" transversely supported under the instep;
2,519,613 to F. K. Urban, Aug. 22, 1950, showed a clampon device with a cylindrical lower surface transverse to the shoe making it easier and safer to walk with an injured foot;
2,526,205 to E. E. Doerschler, Oct. 17, 1950 (Re. U.S. Pat. No. 23,348) showed a rocker-shaped or arcuate ground-engaging surface attachable by wires to a cast; material suggested was rubber, plastic or wood pulp, for expendability.
Taken together these patents suggest that it is known to provide a system of flat topped detachable transversely extending member with length sloped to the front and rear forming a high central support for use under the rigid sole of a shoe or boot as a pivot for easier walking, and to make the member of resilient and/or disposable material.